GB1584875A

GB1584875A - Control device for a windscreen wiper for motor vehicles

Info

Publication number: GB1584875A
Application number: GB3612477A
Authority: GB
Original assignee: Ducellier et Cie
Current assignee: Ducellier et Cie
Priority date: 1976-09-22
Filing date: 1977-08-30
Publication date: 1981-02-18
Also published as: IT1086519B; DE2740295A1; ES461921A1

Description

(54) A CONTROL DEVICE FOR A WINDSCSREEN WIPER FOR MOTOR VEHICLES (71) We, DUCELLIER & CIE, a French Company of Echat 950, 94024 Creteil Cedex, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a driving and control system for a vehicle windscreen wiper, including a windscreen wiper motor driving a rotary switch provided with three conductive tracks each co-operating with a respective wiper brush and a manual switch movable to an inoperative position, permitting the windscreen wiper to be returned to a fixed stop position.

In systems of this type, the stopping of the motor is generally carried out by short circuiting the armature. Although this has no disadvantages when direct earthing is possible, it is not so when an earth connection has to be made on to another electrical control apparatus, since in this case the current inversion causing the short-circuit has to be very sudden in order not to risk sending a damaging return current of positive polarity to a terminal of negative polarity of the said control apparatus.

An object of the present invention is to provide a driving and control system in which rapid inversion is obtained by simple mechanical means, and which also has the advantage of necessitating only 'a single conductor between the manual switch and the motor, instead of the two generally used.

This is of additional interest in the case of the control of a rear windscreen wiper, since it permits several meters of electric wire to be saved on each assembly.

According to the present invention, a driving and control system for a vehicle windscreen wiper comprises a wiper motor, a rotary switch driven by the motor and provided with three conductive tracks cooperating respectively with three wiper brushes, a manual switch movable between operative and non-operative positions, and wherein a first track of the rotary switch is connected by its corresponding brush to the manual switch so as to be connectible to a negative or positive pole of a current source, depending upon which of said positions is occupied by the manual switch, a second track of the rotary switch is electrically insulated from the first track and connected by its corresponding brush to a permanent positive pole, and a third track of the rotary switch is electrically connected to the second track and, via its corresponding brush provides current supply to the motor, said third track having a cut-away portion such that during the passage of the brush, the latter meets a recess, in the base of which it comes suddenly into contact with a conductive section electrically connected to the first track.

In such a system, the addition of an electric pump is sometimes required, the operation of which must be connected to the operation of the windscreen wipers to operate according to a predetermined cycle.

This is achieved in the system of the invention in which the first and second tracks may conveniently be constituted by conductive sections arranged in such a way that the first track ensures both the starting of the drive motor and the supply to a pump.

Moreover, the fact of having a track permanently connected to a positive pole, even when the motor is stopped, can cause an accidental short-circuit, particularly when a sudden cut-off occurs or one brush passes from a positive to a negative polarity in a very short time. A further object of the invention is to provide a drive and control system in which this risk is minimised or avoided.

To this end, the second track is delimited by an insulating portion disposed approximately in line with the first track and the conductive section, which insulating portion ensures the insulation of the permanent permanent positive pole in the stop position of the control device.

The invention will now be described, with reference to the accompanying drawings, in which: Figure 1 shows an electrical diagram of a first embodiment of the control device of the invention; Figure 2 shows an electrical diagram of a second embodiment of the control device of the invention, and Figure 3 shows an electrical diagram of a third embodiment of the control device of the invention.

Referring to Figure 1 of the drawings, this shows a windscreen wiper control circuit including a motor 1 controlled by a manual switch 2, and a control device in the form of a rotary switch 3 driven by the motor.

The manual switch is constituted by a contact bar 4, enabling a contact 5 to be connected either to a contact 6, itself connected to a positive pole of a power supply shown as a battery 8, or to a contact 7 connected to a negative pole depending upon whether the switch is in the I (operative) position or 0 (stop) position. Depending upon the position of the bar 4, the contact 5 is thus connected to the negative or positive pole of the battery.

The rotary switch 3 has a first track 9 in the shape of a disc, the corresponding brush 10 of which is connected to the contact 5 by means of a conductor 5a. The switch also has second and third tracks 11 and 13 made in one piece as a single conductive disc disposed co-axially on the first track 9 with insulating material 15 disposed between them, the second track 11 being permanently connected to a positive pole by means of the brush 12 and the conductor 16, and the third track 13 being of identical polarity to the track 11 and ensuring the supply to the motor 1 by means of a brush 14 and the conductor 17.

The track 13 has a cut-away portion 18 such that during passage of the brush 14, the latter meets a recess, in the base of which it comes into sudden contact with a conductive section 19 electrically connected to the first track 9.

The operation of the device described above is as follows:- When the contact bar 4 is moved from the the position 0, which corresponds to a fixed stop position, to the operative position I, the circuit is closed, making a connection of positive polarity passing through the contacts 6 and 5 and through the brush 10 in contact with the track 9. The latter being itself in contact with the conductive section 19, ensures the supply to the motor 1 by virtue of the brush 14. The effect of this is to start up the motor 1 and consequently to drive the rotary switch 3.

The effect of the rotary movement of the switch 3 is to place the brush 14 in contact with the track 13 which, supplied with positive current in the same way as the track 11, will continue to ensure the supply to the motor 1. If the switch 2 is left in the position I, the cycle will be repetitive, since, when the brush 14 returns to the level of the conductive section 19, it will still receive a positive polarity. When, during operation, the bar 4 of the switch is moved back to a stop position 0, this will have the effect of reversing the polarity of the track 9 and the section 19.

This does not prevent the motor from finishing its cycle, but when the brush 14 meets the cut-away portion 18, it will come suddenly into contact with the conductive section 19, which, being of negative polarity, will cause the motor 1 to stop in a fixed stop position of the windscreen wipers.

The embodiment shown in Figure 2 differs essentially from the foregoing in that the first track 20 and the second and third tracks 21 and 22 are formed on two concentric drums having insulating meterial 23 disposed between them.

In this embodiment, the brushes 10, 12 and 14 will bear tangentially on the tracks with respect to the axis of the rotary switch 3.

In another embodiment (Figure 3) the manual switch 2 is constituted by a contact bar 4 enabling a contact 5 to be connected to a contact 6, itself connected to a positive pole of the battery 8, or to a contact 7 connected to a negative pole, depending upon whether the switch is in the I (operative) or 0 (stop) position. Depending upon the position of the bar 4, the contact 5 is thus connected either to the positive pole or to the negative pole of the battery 8.

The rotary switch 3 has a first quadrantshaped conductive track 9 extended in the same plane by an insulating portion 9a so as to form a disc. A corresponding brush 10 is connected to the contact 5 by means of a conductor 5a and permits the starting of the motor 1, as well as establishing current supply to a pump 30. Second and third tracks 11 and 13 are made in one piece in a single conductive section disposed co-axially on the first track 9 with insulating material disposed between them, the second track 11 being delimited by an insulating portion 31 disposed approximately in line with the first track 9 and which is connected to a permanent positive pole by means of a brush 12 and the conductor 16. The insulating portion 31 thus ensures the insulation of the permanent positive pole in the stop position of the device.

The third track 13 is of the same polarity as the track 11 and ensures the supply to the motor 1 by means of the corresponding brush 14 and of the conductor 17. The track 13 has a cut-away portion 18 such that during passage of the brush 14, the latter meets a recess in the base of which it comes into sudden contact with the conductive section 19 electrically connected to the first track 9.

The operation of the device described above is as follows: When the contact bar 4 is moved from the position 0 which corresponds to a fixed stop position, to the operative position I, the circuits are closed making a connection of positive polarity passing through the contacts 6 and 5 and through the brushes 10 and 32 in contact with the track 9. Since the track 9 is itself in connection with the conductive section 19, this ensures both the supply to the motor 1 by means of the brush 14 and the supply to the pump 30 by means of the brush 32. This has the effect of starting the motor 1 which drives the rotary switch 3.

The operating time of the pump is defined by the length of the quadrant-shaped track 9.

The rotary movement of the switch 3 has the effect of placing the brush 14 in contact on the track 13 which, supplied with positive current at the same moment as the track 11, will continue to ensure the supply to the motor 1. If the switch 2 is left in the position I, the cycle will be repetitive, since, when the brush 14 returns to the level of the conductive section 19, it will still receive a positive polarity.

When, during operation, the bar 4 of the switch 2 is returned to a stop position 0, the effect will be to connect the track 9 as well as the section 19, not to a positive, but to a negative polarity. This does not prevent the motor from completing its cycle, but when the brush 14 meets the cut-away portion 18, it will come suddenly into contact with the conductive section 19 which, being of negative polarity, will cause the motor 1 to stop in a fixed stop position of the wipers. At this moment, the brush 12 connected to a positive polarity will be in contact with an insulating portion 31 and the tracks 11 and 13 will thus be insulated from any positive polarity.

It is understood that many modifications may be made to these embodiments, such as, for example, in the second embodiment the conductive tracks may be disposed within the drums and in this case the brushes will also be disposed within the drums.

WHAT WE CLAIM IS: 1. A driving and control system for a vehicle windscreen wiper, comprising a wiper motor, a rotary switch driven by the motor and provided with three conductive tracks co-operating respectively with three wiper brushes, a manual switch movable between operative and non-operative positions, and wherein a first track of the rotary switch is connected by its corresponding brush to the manual switch so as to be connectible to a negative or positive pole of a current source, depending upon which of said positions is occupied by the manual switch, a second track of the rotary switch is electrically insulated from the first track and connected by its corresponding brush to a permanent positive pole, and a third track of the rotary switch is electrically connected to the second track and, via its corresponding brush provides current supply to the motor said third track having a cutaway portion such that during the passage of the brush, the latter meets a recess, in the base of which it comes suddenly into contact with a conductive section electrically connected to the first track.

2. A system according to Claim 1, wherein the conductive section is made in one piece with the first track in the shape of a disc.

3. A system according to Claim 1, wherein the conductive section is made in one piece with the first track in the shape of a drum.

4. A system according to Claim 1 or Claim 2, wherein the second and the third tracks are made in one piece as a single conductive disc disposed co-axially on the first track with insulating material disposed between is them, such that the cut-away portion is opposite to the conductive section.

5. A system according to Claim 1 or Claim 3, wherein the second and third tracks are made in one piece in a single conductive drum disposed concentrically with respect to the first track, having insulating material disposed between them, so that the cut-away portion is opposite to the conductive section.

6. A system according to Claim 1 more particularly adapted to supply a windscreen washer pump in an intermittent manner, wherein the first and second tracks are constituted by conductive sections arranged in such a way that the first track ensures both the starting of the motor and the supply to the pump.

7. A system according to Claim 1 and Claim 6, wherein the second track is delimited by an insulating portion disposed approximately in line with the first track and with the conductive section, which insulating portion ensures the insulation of the permanent positive pole in the stop position of the control device.

8. A driving and control system for a vehicle windscreen wiper substantially as hereinbefore described with reference to Figure 1, Figure 2 or Figure 3 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. The operation of the device described above is as follows: When the contact bar 4 is moved from the position 0 which corresponds to a fixed stop position, to the operative position I, the circuits are closed making a connection of positive polarity passing through the contacts 6 and 5 and through the brushes 10 and 32 in contact with the track 9. Since the track 9 is itself in connection with the conductive section 19, this ensures both the supply to the motor 1 by means of the brush 14 and the supply to the pump 30 by means of the brush 32. This has the effect of starting the motor 1 which drives the rotary switch 3. The operating time of the pump is defined by the length of the quadrant-shaped track 9. The rotary movement of the switch 3 has the effect of placing the brush 14 in contact on the track 13 which, supplied with positive current at the same moment as the track 11, will continue to ensure the supply to the motor 1. If the switch 2 is left in the position I, the cycle will be repetitive, since, when the brush 14 returns to the level of the conductive section 19, it will still receive a positive polarity. When, during operation, the bar 4 of the switch 2 is returned to a stop position 0, the effect will be to connect the track 9 as well as the section 19, not to a positive, but to a negative polarity. This does not prevent the motor from completing its cycle, but when the brush 14 meets the cut-away portion 18, it will come suddenly into contact with the conductive section 19 which, being of negative polarity, will cause the motor 1 to stop in a fixed stop position of the wipers. At this moment, the brush 12 connected to a positive polarity will be in contact with an insulating portion 31 and the tracks 11 and 13 will thus be insulated from any positive polarity. It is understood that many modifications may be made to these embodiments, such as, for example, in the second embodiment the conductive tracks may be disposed within the drums and in this case the brushes will also be disposed within the drums. WHAT WE CLAIM IS:

1. A driving and control system for a vehicle windscreen wiper, comprising a wiper motor, a rotary switch driven by the motor and provided with three conductive tracks co-operating respectively with three wiper brushes, a manual switch movable between operative and non-operative positions, and wherein a first track of the rotary switch is connected by its corresponding brush to the manual switch so as to be connectible to a negative or positive pole of a current source, depending upon which of said positions is occupied by the manual switch, a second track of the rotary switch is electrically insulated from the first track and connected by its corresponding brush to a permanent positive pole, and a third track of the rotary switch is electrically connected to the second track and, via its corresponding brush provides current supply to the motor said third track having a cutaway portion such that during the passage of the brush, the latter meets a recess, in the base of which it comes suddenly into contact with a conductive section electrically connected to the first track.